Fixes#1478
When a terminal reports cwd as '~' or '~/subpath' instead of the full
path, getProjectName() fell through to the 'unknown-project' fallback
because path.basename('~') returns '~' as-is.
Added expandTilde() helper that resolves leading ~ to os.homedir(),
called in both getProjectName() and getProjectContext() before path
operations and worktree detection.
JasonOA888